Studies conducted by the Neuropathology Core during the previous period of funding Core in collaboration with other components of the ADRC and national and international researchers have been instrumental in delineating structural correlates of dementia in AD, identifying new neuropathological entities causing dementia, in helping to determine relationships between genotype and neuropathology and better understanding the mechanisms of neurodegeneration in AD. In this context, the main objective of the Neuropathology Core is to provide the projects and other Cores with expert state of the art neuropathological analysis and high quality, well characterized brain tissues from controls, early/moderate severe AD, and DLB cases. In this context the specific aims are: 1) To obtain brains from the Alzheimer Disease Research Center (ADRC) participants within 8 hrs after death, using a standardized protocol. 2) To provide neuropathological diagnoses of demented and normal aged (control) patients clinically evaluated by the San Diego ADRC, using standardized methods. 3) To perform lesion counts and Braak staging for AD and Dementia with Lewy bodies Disease (DLB). 4) To perform neurochemical analysis relevant to neurodegeneration and amyloid production in frozen brain samples. 5) To maintain a state of the art Alzheimer's brain bank with well characterized cases including Mild Cognitive Impairment (MCI) cases. This resource will continue to provide high quality fresh, frozen and fixed brain tissues to ADRC researchers as well as to national and international collaborators. Special emphasis will be placed at obtaining cases with MCI. The neuropathological and neurochemical data collected in these cases will be used for subsequent clinico-pathological correlations. A web-based database and web site is maintained for tissue requests, tissue logs and disbursements. The Core also provides data and tissues to other components of the ADRC and to national and international collaborators.